If you are asking in general it is because I'm out of practice. If you are only asking about the kick it is because I'm trying to make space. If my distancing was better I wouldn't have to lean back as much. I think you still have to lean back a little to kick high but that can also be reduced with better flexibility.

I know it was just a critique because I was going to say to cope for being so close to him you dont need to lean back as that throws you off balance when you can just roll your hips and shoulders off to the side and that helps your balance and gives you distance from his punches. Also to get your kicks higher or atleast what i do is just come up on your toes.

I have heard to do both. I know that in Thai Style they tend to favor the switch more. Some times the switch is good because you can play around with you opponet using it. For example you can fient by switching your legs one extra time.

Dutch style told me to never switch because it telegraphs your attack. I guess it is up to personal perference.